Together with recent progress in the digital audio technology, associated technologies for converting analog audio signals into digital signals and recording them on a tape are developed. Since a significantly wide exclusive frequency band is required to convert analog signals into digital signals, a magnetic head for signal recording or reproduction on a tape must have a wide contact area per unit time. In this respect, it is indispensable to replace a conventional fixed-head arrangement by a rotary head arrangement. Therefore, various tape recorders including a rotary head have been proposed to meet the requirement.
A tape recorder or other magnetic recording apparatus including a rotary head is configured so that loading blocks pull out the tape from a tape cassette after the tape cassette is loaded, and the loading blocks subseqently wind the tape on the rotary head. This arrangement requires that a pinch roller for establishing close contact between the tape and a capstan is movable back and forth as the loading blocks are.
In this case, the loading blocks and the pinch roller take near and parallel positions before tape loading, but they move toward the rotary head along their respective arcuate orbits. Therefore, a significant space is required for their motions. This invites a dimensional increase of the mechanism in some cases in which sufficient space is reserved for respective motions of these members.
A proposed countermeasure against this problem is to partly overlap the moving area of the loading block with the moving area of the pinch roller to decrease the entire moving space. This arrangement, however, requires control of timings of motions of the pinch roller and the loading block so as to prevent any interference between them. In this connection, one of the prior art mechanisms is provided with a timing regulating arrangement using a cam slot provided in a driving gear connected to a loading motor for engagement with a cam plate. However, this arrangement is complicated and still results in a dimensional increase of the mechanism. This is against a strong demand of dimensional reduction of a tape recorder particularly for use in a car.
Beside this, such a conventional pinch roller is configured so that its shaft supported pivotably with respect to a driving member such as a pinch roller arm is moved along a guide groove. Therefore, there remains a further problem that a possible inclination of the shaft causes an unreliable operation of the pinch roller, for example.
Further, the pinch roller in the prior art arrangement effects two motions, i.e. back and forth movement in a tape loading operation and movement for close contact with the capstan.
A prior art arrangement for effecting back and forth movement and close contact motion of the pinch roller is such that the shaft of the pinch roller is connected to one end of a pivotable pinch roller arm so that the pinch roller shaft moves back and forth along a guide groove in its back and forth motion whereas the pinch roller shaft is rotated by pushing the pinch roller arm in its close contact motion. However, this arrangement involves a problem that the pinch roller inclines in its back and forth motion or in the close contact motion and invites unreliable operation of the mechanism. Additionally, since the pinch roller arm has a flexibility to effect both operations for back and forth motion and close contact motion of the pinch roller, it is difficult for the pinch roller arm to reliably guide the pinch roller to a position ready for close contact (stop mode position) and hold it there. This sometimes results in forcible compression to the pinch roller in an erroneous position or an erroneous timing of the urging motion, which causes the pinch roller to move in an erroneous direction unabling reliable close contact with the capstan shaft.